Well drilling apparatus



y 5, 1966 J. E. LACY ETAL WELL DRILLING APPARATUS Filed Oct. 9, 1965 F I G. 2

FIG. 3

FlG. 4

INVENTORS J. E. LACY FIG.

F. F. MARTIN a Hm THEIR AGENT United States Patent 3,259,197 WELL DRILLING APPARATUS John E. Lacy, Metairie, and Fines F. Martin, New 0rleans, La., assignors to Shell Oil Company, New York, NY, a corporation of Delaware Filed Oct. 9, 1963, Ser. No. 314,936 5 Claims. (Cl. 175-5) This invention relates to well drilling apparatus and pertains more particularly to apparatus used for rotating a string of pipe, commonly known as a drill string, when drilling a well by the rotary method. The invention is particularly applicable for use on a drilling vessel from which floating drilling and completion of underwater wells are being carried out.

During recent years, the continued search for oil has resulted in developing methods and apparatus for drilling underwater wells at locations where the water may range from 100 to 1500 feet or more in depth. In these locations it is customary to position the wellhead at a considerable distance below the surface of the Water, preferably on the ocean floor, so that it is not a hazard to the navigation of ships in the area. Most wells drilled in water over 100 feet deep are drilled from floating drilling vessels, barges or platforms which are anchored at a predetermined location offshore.

A drilling vessel is generally provided with a suitable derrick for suspending drilling tools therefrom, and a rotary table for rotating a drill string extending from the vessel to the ocean floor and down into the well being drilled. From time to time it is necessary to run various well tools or well apparatus, for example a well casing or conductor pipe string, down from the vessel into the well. These operations are normally carried out by suspending the tool or pipe or casing string being run from the fall line system of the derrick on the vessel and running it through the rotary table on the operating floor after the central bushing has been removed from the rotary table. The central bushing is removed so that largediameter equipment can be run down through the rotary table while using the derrick suspension system which is centered over it.

Thus, for example, when the main or central bushing has been removed from one particular rotary table used on an offshore drilling vessel, the opening through the rotary table is 27 /2 inches in diameter. In starting an underwater well, a foundation casing of say 100 feet of pipe 26 inches in diameter may be lowered from the vessel and forced or jetted into the ocean floor by suitable weights and/or jetting equipment releasably secured to the top of the foundation casing. After the foundation casing has been sunk in the ocean floor to the desired level, the weighting apparatus and/ or jetting equipment is removed by disconnecting it from the foundation casing and pulling it upwardly through the central opening in the rotary table on the vessel. In pulling equipment of this type up through the opening in the rotary table by means of the hoist system of the derrick, there is the danger that a portion of the apparatus will hang up on the edge of the hole through the rotary'table with the result that either the equipment being withdrawn or the rotary table is damaged. In extreme cases the rotary table would be pulled oif the operating deck to which it is fastened.

This danger of damaging drilling equipment or the rotary table of a drilling vessel is a common hazard encountered when drilling wells at offshore locations from a floating vessel due to the fact that it is impossible to anchor the vessel at any one spot in the oceanwithout there being some some movement to the vessel. Additionally, since equipment being withdrawn to the vessel is subjected to wind and wave forces in the 50 or 100 feet of space between the operating deck and the normal water line, the equipment may sway or be forced to one side of the central opening through the rotary table. Thus, in withdrawing a drill string or running string upwardly through the rotary table, any outwardly extending tool or apparatus such as a running tool, drill bit, drill collars, etc. may hang up on the lower edge of the rotary table and damage it.

It is therefore a primary object of the present invention to provide means associated with a rotary table whereby any well tool or apparatus to be drawn up through the central opening of the rotary table is brought into axial alignment with the opening prior to entering the opening.

A further object of the present invention is to provide apparatus secured to a drilling vessel independent of a rotary table while being aligned with the rotary table for bringing well tools or pieces of well apparatus into register with the central opening through the rotary table before they are pulled upwardly therethrough.

These and other objects of this invention will be understood from the following description taken with reference to the drawing, wherein:

FIGURE 1 is a diagrammatic view, taken in partial longitudinal section illustrating one form of a floating drilling vessel positioned over an underwater well with a drill string extending from a vessel into the well borehole.

FIGURE 2 is an enlarged fragmental view showing the manner in which a tool and equipment guide is mounted on the vessel relative to the rotary table on the operating deck of the vessel.

FIGURE 3 is a schematic view taken in partial cross section illustrating one form of a rotary table wherein the tool and equipment guide of the present invention is secured to the lower edge of the rotary table; and,

FIGURE 4 is a view, taken in partial cross section, of another form of a rotary table wherein the tool and equipment guide of the present invention is secured to the rotary table housing.

Referring to FIGURE 1 of the drawing, a drilling vessel, barge or platform 11, of any suitable floating or floatable type is illustrated as floating on the surface of a body of water 12 while being substantially fixedly positioned over a preselected Well location by suitable vessel positioning means well known to the art, or by being anchored to the ocean floor 13 by anchor lines running to anchors (not shown). Equipment of this type may be used when carrying on well drilling operations or well workover operations in water varying from about feet to 1500 feet or more in depth. The drilling vessel 11 is equipped with a suitable derrick 16 containing a fall line system 17 which includes a suitable hoist 18, travelling block 19 and suitable hook and swivel or other connector means 20 adapted to be connected to the top 1 of a drill pipe 21 during well drilling operations and being adapted to circulate a drilling fluid therethrough, in a manner well known to the art, when needed. A kelly 22, which is a section of pipe having a square or nonround outer surface, is interposed between the top pipe section of the drill string 21 and swivel 20. It is to be understood that a hose for circulating mud into the top of the drill string would be connected to the swivel 20.

The vessel 11 is also provided with other auxiliary equipment needed during well drilling operations, such for example as a rotary table 24 positioned on the operat ing deck 25 of the vessel. A rotary table drive mechanism is positioned on or under the operating deck 25 and is connected through a' drive shaft 27 to the rotary table 24. A tool and equipment guide 30 is illustrated as being fixedly secured to support members beneath the operating platform 25. The derrick 16 is positioned over a drilling slot or well, if desired which extends vertically through the vessel in a conventional manner. Alternatively, drilling operations may be carried out over the side of the vessel without the use of a slot. For example, the drilling vessel 11 may be provided with a deck portion which overhangs the hull of the vessel as illustrated in FIGURE 1.

Although for ease of illustration, the drill string 21 is shown as a unitary length of pipe, it is well known that a pipe string or drill string used in well drilling operations is made up by threadedly connecting together several short (say 30 feet) sections of pipe to make up a pipe string of the desired length. A drill bit 31 is secured to the lower end of the drill string and generally one or more of the bottom sections of pipe forming the lower end of the drill string 21 may be thick-walled pipe in the form of drill collars 32, if desired. In withdrawing a drill string back to the vessel, the upper edge of the uppermost drill collars, or the drill bit, may hang up on the bottom of the rotary table unless they are brought into proper alignment with the central vertical opening through the rotary table which may be moving with the moving vessel.

The rotary table 24 of FIGURE 1 is shown in greater detail in FIGURE 2 to rest on rotary table support beams 33 and 34 to which it may be bolted. The tool and equipment guide 30 is shown as being axially positioned between the central opening 35 of the rotary table. The tool and equipment guide 30 may be secured to the vessel in any suitable manner, as \by being fixedly secured to the rotary table support beams 33 and 34 by means of laterally extending arms 36 and 37 welded thereto. It is to be understood that the tool and equipment guide 30 may be either a unitary structure, as shown, or may comprise one or more downwardly and outwardly sloping guide elements attached to the inner ends of the arms 36 and 37 and arranged at an angle suflicient to guide upwardly-moving tools or equipment into the center of the guide 30 and into the axial bore 35 of the rotary table 24. Preferably the upper end of the tool and equipment guide 30 is provided with at least a short vertical section 38 to cause the tool or pipe passing therethr-ough to be brought into vertical alignment before it enters the central'opening in the rotary table. For purposes of illustration, a section of well casing 39 is shown as extending through the guide 30 and rotary table 24. The guide 30 is preferably fixedly secured to the platform by arms 36 and 37 in spaced relationship with the bottom of the rotary table housing and in axial alignment with the axial bore of the rotary table so that in the event that a tool or piece of equipment should strike the bottom of the cone-shaped guide 30 with ocnsiderable force, there would be no jarring action imparted to the rotary table 24.

However, it is to be understood that in some circumstances the tool and equipment guide 30 can be secured to the rotary table itself. While in the description hereinabove the rotary table has been referred to generally as numeral 24, from an equipment standpoint the rotary table is actually the rotating element or table 40 mounted on bearings 41 and 42 within the rotary table housing 43. The rotary table 40 is provided with a ring gear 44 which is engaged by a pinion 45 secured to the shaft 27 which is mounted on suitable bearings 46 and 47. As shown in FIGURE 3, the tool and squipment guide 30 is fixedly secured to the lower edge of the rotary table in any suitable manner, as by bolts 48. While the tool and equipment guide 30 slopes downwardly and outwardly preferably at an angle of 45 this angle may vary anywhere from to 60 to the vertical or to the axis through the central opening or axial bore 49 through the rotary table 40. The height of the tool and equipment guide may be relatively short if sloping at say 45. Thus, on the large size rotary table having an opening 49 therethrough of 27 /2 inches, a guide 30 only 6 inches high would have a lower opening of about 40 inches in diameter to aid in bringing tools or other pieces of equipment into alignment with the opening through the rotary table.

Another combination of rotary table 40 and guide element 30 is illustrated in FIGURE 4 wherein the tool and equipment guide 30 is rigidly secured to the rotary table housing 43 in any suitable manner, as by bolts 50. This arrangement is preferable to that illustrated in FIG- URE 3 as from a cost standpoint it is not necessary to get the guide element 30 perfectly balanced for rotation with the rotary table 40.

Thus, it may be seen that the apparatus of the present invention is extremely useful when drilling from anchored or moving offshore vessels but it is not necessarily limited thereto. It reduces danger or damage to equipment on or about the rig and hence reduces operational hazards for the operators.

We claim as our invention:

1. Apparatus for use with well tools and equipment used in drilling oil and gas wells, said apparatus comprising a rotary table'housing having aligned openings in the top and bottom thereof and adapted to be secured in a fixed manner to a drilling platform,

a rotary table mounted within said rotary table housing for rotation about a vertical axis, said rotary table having a vertically-disposed axial bore therethrough for passing well tools and equipment therethrough, said bore being in register with the aligned openings of said rotary table housing,

tool and equipment guide means substantially rigidly mounted to saidapparatus adjacent and below said rotary table and coaxially with the bore therethrough, said guide means having a central opening of an internal diameter no greater than the axial bore of said rotary table, said guide means extending downwardly and outwardly from said rotary table at an angle suflicient to guide upwardly moving tools and equipment into the axial bore of said rotary table, and to a point laterally-displaced from the opening at the bottom of said rotary table housing to aid in aligning tools within the opening.

2. The apparatus of claim 1 wherein said tool and equiment guide means are fixedly secured to the lower end of the rotary table for rotation therewith.

3. The apparatus of claim 1 wherein said tool and equipment guide means are fixedly secured to said rotary table housing in a stationary manner and being in axial alignment with the axial bore of said rotary table.

4. The apparatus of claim 1 wherein the tool and equipment guide means comprises a cylindrical Wall member having downwardly and outwardly sloping walls.

5. The aparatus of claim 4 wherein the walls of said tool and equipment guide means slope at an angle downwardly of from 25 to 60 degrees to the vertical.

References Cited by the Examiner UNITED STATES PATENTS 1,938,020 12/1933 Hild ll95 X 1,971,473 8/1934 Zerbe et al. l95 2,222,082. 11/1940 Leman et al. l75l95 2,390,601 12/1945 Maier l75'-l95 2,506,538 5/1950 Bennett l75l95 3,032,125 5/1962 Hiser et a1 166-665 X 3,110,350 11/1963 Spiri 175-5 3,142,337 7/1964 Poorman et a1 16666.5 3,142,343 7/ 1964 Otternan et al. l757 CHARLES E. OCONNELL, Primary Examiner.

R. E. FAVREAU, Assistant Examiner. 

1. APPARATUS FOR USE WITH WELL TOOLS AND EQUIPMENT USED IN DRILLING OIL AND GAS WELLS, SAID APPARATUS COMPRISING A ROTARY TABLE HOSUING HAVING ALIGNED OPENINGS IN THE TOP AND BOTTOM THEREOF AND ADAPTED TO BE SECURED IN A FIXED MANNER TO A DRILLING PLATFORM, A ROTARY TABLE MOUNTED WITHIN SAID ROTARY TABLE HOUSING FOR ROTATION ABOUT A VERTICAL AXIS, SAID ROTARY TABLE HAVING A VERTICALLY-DISPOSED AXIAL BORE THERETHROUGH FOR PASSING WELL TOOLS AND EQUIPMENT THERETHROUGH, SAID BORE BEING IN REGISTER WITH THE ALIGNED OPENINGS OF SAID ROTARY TABLE HOUSING, TOOL AND EQUIPMENT GUIDE MEANS SUBSTANTIALLY RIGIDLY MOUNTED TO SAID APPARATUS ADJACENT AND BELOW SAID ROTARY TABLE AND COAXIALLY WITH THE BORE THERETHROUGH, SAID GUIDE MEANS HAVING A CENTRAL OPENING OF AN INTERNAL DIAMETER NO GREATER THAN THE AXIAL BORE OF SAID ROTARY TABLE, SAID GUIDE MEANS EXTENDING DOWNWARDLY AND OUTWARDLY FROM SAID ROTARY TABLE AT AN ANGLE SUFFICIENT TO GUIDE UPWARDLY MOVING TOOLS AND EQUIPMENT INTO THE AXIAL BORE OF SAID ROTARY TABLE, AND TO A POINT LATERALLY-DIAPLACED FROM THE OPENING AT THE BOTTOM OF AID ROTARY TABLE HOUSING TO AID IN ALIGNING TOOLS WITHIN THE OPENING. 